Two single-sided solar panels are MESSENGER's main source of electrical power

Press Release

08 June 2011

REDONDO BEACH, Calif., June 8, 2011 (GLOBE NEWSWIRE) -- Key technologies and hardware
developed by Northrop Grumman Corporation (NYSE:NOC) gave the first spacecraft to orbit
Mercury a power system that works to its maximum even in the searing heat that surrounds
the planet closest to the sun.

The solar array on NASA's MErcury Surface, Space ENvironment, GEochemistry,
and Ranging (MESSENGER) spacecraft features
advanced triple-junction gallium arsenide solar cells
and an electrical harness developed and qualified for this
mission by Northrop Grumman Aerospace Systems.
The company also perfected a fully robotic welding process
to assemble the photovoltaic cells before they were bonded
to the solar array panel. The work was done under the pressure
of meeting a launch window that was so tight that missing it would
have meant a year-long wait until the next launch opportunity.

"When it launched in 2004, MESSENGER was the first Northrop Grumman program
to use these advanced solar cells, electrical designs and welding processes
that now are the baseline for all our major programs, including the James Webb Space Telescope
and the Defense Weather Satellite System," said Tim Frei, vice president,
system enhancements and product applications for Northrop Grumman Aerospace Systems.
"Our depth of talent and the processes we developed enabled us to perfect the
technology needed for spacecraft to perform under very harsh conditions."

Solar array performance is critical – if it fails, so does the mission.
Two single-sided solar panels are MESSENGER's main source of electrical power.
They are two-thirds mirrors and one-third solar cells. The mirrors reflect the
sun's energy and keep the panels cooler. The panels also rotate away from the
sun to get the required power and maintain an operating temperature of about 300 F.

Since its launch, MESSENGER has completed one swing past Earth,
two Venus flybys and three Mercury flybys. By using the gravity of each planet
to gain speed and alter its trajectory, MESSENGER was able to conserve the fuel
it will need during its mission orbiting a planet that is only 29 million miles
from the sun, about two thirds closer to the sun than Earth. At Mercury's equator,
surface temperatures become hot enough to melt lead. The spacecraft's fast,
elliptical orbit allows it to approach Mercury, gather data and swing out far
into space to cool down.

MESSENGER is a NASA Discovery program spacecraft designed and built
by the Johns Hopkins University Applied Physics Laboratory, Laurel,
Md. The probe completed a six-and-a-half-year journey prior to its March 17 insertion
into orbit around the planet closest to our sun. MESSENGER will orbit 730 times
around Mercury for a year.

In the Picture:
The solar cells and electrical harness for the MESSENGER
spacecraft were built by Northrop Grumman Aerospace Systems
as shown here by Manufacturing Sub-Project manager Suzi Waldie.